Visual and structural prognosis of the untreated fellow eyes of unilateral normal tension glaucoma patients

Rapid Retinal Nerve Fiber Layer Thinning in the Unaffected Contralateral Eyes of Patients with Unilateral Normal-Tension Glaucoma: A Retrospective Observational Study

PURPOSE

To observe the rate of progressive retinal nerve fiber layer (RNFL) thinning in the unaffected eyes of patients with unilateral normal-tension glaucoma (NTG), in comparison with that of healthy subjects, and to identify the factors associated with progressive RNFL thinning.

DESIGN

Retrospective, longitudinal, observational study.

PARTICIPANTS

Ninety-five patients with unilateral NTG and 61 healthy controls.

METHODS

This study included unilateral NTG and healthy control subjects who were followed up for longer than 4 years and in whom at least 5 reliable retinal nerve fiber layer thickness (RNFLT) measurements were performed using OCT. Factors associated with the rate of thinning of the unaffected eyes of unilateral patients with NTG were identified using regression analysis.

MAIN OUTCOME MEASURES

The rate of progressive RNFL thinning and the associated factors.

RESULTS

Retinal nerve fiber layer thickness decreased significantly in both the unaffected eyes of unilateral patients with NTG and the healthy eyes (both P < 0.001). The RNFL thinning was significantly faster in the unaffected eyes of unilateral patients with NTG than in the healthy eyes (P < 0.001), specifically in the temporal-inferior (TI) sector (P = 0.003). Factors associated with faster RNFL thinning in the unaffected eyes of unilateral patients with NTG were thicker baseline RNFL of the unaffected eyes (P = 0.002) and a worse visual field (VF) mean deviation (MD) in the NTG eyes (P = 0.040). In the healthy controls, the rate of RNFL thinning in the contralateral eyes was the only factor associated with faster thinning (P = 0.007).

CONCLUSIONS

The unaffected eyes of unilateral patients with NTG showed faster RNFL thinning than healthy control eyes, more obviously in the TI sector, and were likely to progress faster when they had a thicker baseline RNFL, and when the NTG eyes had a worse VF MD. In unilateral patients with NTG, initiation of prophylactic treatment could be considered for the unaffected eyes when they are accompanied by a risk of developing glaucoma.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Intereye comparison of visual field progression in eyes with open-angle glaucoma

PURPOSE

To investigate the intereye correlations between and differences in the rates of visual field (VF) progression in eyes with bilateral open-angle glaucoma.

STUDY DESIGN

Retrospective, longitudinal, observational study.

METHODS

Patients with bilateral open-angle glaucoma with 8 or more reliable 30 - 2 standard automated perimetry tests over a period of more than 2 years were enrolled. The rate of change of the MD (MD slope) was used as the indicator for the rates of VF progression. Descriptive statistics of the absolute intereye difference in the MD slope values were computed. Factors associated with a large intereye difference (> 0.42 dB/year) were explored.

RESULTS

One hundred eighty-eight eyes from 94 patients (56 women) were enrolled. A significant intereye correlation of the rates of visual field progression (P = .002) was found. The mean ± standard deviation and median intereye differences of the MD slope values were 0.29 ± 0.31 and 0.18 dB/year (range: 0-1.41), respectively. The 5th, 10th, 25th, 75th, 90th, and 95th percentiles of intereye differences were 0.01, 0.02, 0.08, 0.42, 0.72, and 0.91 dB/year, respectively. Older age and slower progression were significantly associated with large intereye difference.

CONCLUSION

A significant intereye correlation in the rate of VF progression was found in eyes with bilateral open-angle glaucoma. We showed the distributions and associated factors of intereye differences in VF progression. These data may be used for improving the estimation of rates of VF progression.

Relationship of axial length and corneal biomechanical properties with susceptibility to unilateral normal-tension glaucoma

PURPOSE

Corneal biomechanics, reflecting structural vulnerabilities of the eyeball, may participate in the pathogenesis of unilateral normal-tension glaucoma. This study investigated the pathophysiology of unilateral normal-tension glaucoma using Corvis ST (OCULUS Optikgeräte GmbH) and other ocular characteristics.

METHODS

Eighty-three patients with normal-tension glaucoma with unilateral visual field loss and structurally unaffected fellow eyes and 111 healthy controls were included in this prospective study. Dynamic corneal response parameters, intraocular pressure measured by rebound tonometry, central corneal thickness, and axial length were assessed on the same day. Measurements were compared between affected eyes, unaffected fellow eyes, and control eyes. Risk factors for normal-tension glaucoma and unilateral involvement were the main outcome measures.

RESULTS

A shorter first applanation time (adjusted odds ratio, 0.061; 95% confidence interval, 0.018-0.215) and a larger peak distance (adjusted odds ratio, 4.935; 95% confidence interval, 1.547-15.739) were significant risk factors for normal-tension glaucoma and were associated with greater glaucoma severity (both P < 0.001). Axial length (adjusted odds ratio, 29.015; 95% confidence interval, 4.452-189.083) was the predominant risk factor for unilateral involvement in patients with normal-tension glaucoma.

CONCLUSION

The eyes with normal-tension glaucoma were more compliant than healthy eyes. Axial elongation-associated optic nerve strain may play an important role in unilateral normal-tension glaucoma with similar corneal and scleral biomechanics in both eyes.

Glaucoma conversion of the contralateral eye in unilateral normal-tension glaucoma patients: a 5-year follow-up study

BACKGROUND/AIMS

To investigate clinical characteristics and risk factors for glaucoma conversion of the contralateral eye in unilateral normal-tension glaucoma (NTG) patients.

METHODS

A retrospective observational cohort study was conducted on a total of 76 subjects who had been diagnosed with unilateral NTG at the baseline and followed up for more than 5 years. Glaucoma conversion in the contralateral eye was defined as increased thinning of neuro-retinal rim, development of retinal nerve fibre layer defect and/or development of glaucomatous visual field defect.

RESULTS

During the mean follow-up period of 7.3±2.4 years, 21 of 76 (27.6%) subjects were confirmed to have developed glaucoma in the non-glaucomatous contralateral eye. The 5-year rate of glaucoma conversion in contralateral eyes was 19.7%. The maximum width of β-zone parapapillary atrophy (MWβPPA)-disc diameter (DD) ratio at the baseline and the presence rate of disc haemorrhage during follow-up period were significantly greater in the contralateral eyes of the conversion group than in those of the non-conversion group (p=0.011, <0.001, respectively). A multivariate Cox-proportional hazard model revealed intraocular pressure (IOP) over 17 mm Hg (HR 5.05, p=0.031), central corneal thickness (CCT) under 491 μm (HR 4.25, p=0.025) and MWβPPA-DD ratio over 0.32 (HR 6.25, p=0.003) in contralateral eye at the baseline as the independent risk factors for glaucoma conversion.

CONCLUSIONS

Among unilateral NTG patients, those with low CCT and high MWβPPA-DD ratio as well as high IOP in the contralateral eye are more likely to develop glaucoma in that eye during long-term follow-up.

The impact of disc hemorrhage studies on our understanding of glaucoma: a systematic review 50 years after the rediscovery of disc hemorrhage

PURPOSE OF REVIEW

To trace the influence of disc hemorrhage studies on our understanding of glaucoma.

SOURCES

Major articles published during the last 50 years since the rediscovery of disc hemorrhage were identified. A total of 196 articles were selected from 435 articles retrieved using the keywords glaucoma and disc hemorrhage as of August 9 2018 from PubMed.

RECENT FINDINGS

The main characteristics of disc hemorrhage, including its morphology, recurrence rate, duration, increased incidence in glaucoma, and role in the progression of normal tension glaucoma was well understood by the year 2000. Since then, studies have focused on more sophisticated and accurate methods of elucidating both structural and functional progression, with special attention to the role of the lamina cribrosa. Nevertheless, both the mechanism of disc hemorrhage development and its fuller relationship with glaucoma remain unclear. Disc hemorrhage research requires careful study of glaucomatous optic neuropathy. This has been facilitated by recent advances in optical coherence tomography (OCT) angiography and other OCT technologies. Furthermore, animal studies of disc hemorrhage promise new insights into glaucomatous optic neuropathy.